Roots 5.125" blower snout coupler. This snout coupler is made from billet heat treated steel that is black oxide finish and can be used with 5/16" bolts. The bore for the gear is 1.250" and the overall length is 2.80".
This coupler can be used with all 1.250" 48 spline blower drive shafts but can be bored out to fit 1.50" register if the racer needs.
RBS stocks a full inventory of grade 8 bolts for the coupler if the racer needs #500-5012 for a socket head allen bolt or #400-5012 for a twelve point.